Improvement in trammels for ellipses



C. CROW.

- Trammel for Ellipses. No. 53,524. PatentedjMqrch 27,1866n UNITE STATESPATENT FFICE.D

CHARLES CROW, OF ONARGA, ILLINOIS, ASSIGNOR TO HIMSELE AND JAMESHOLLINGSWORTH, OF THE SAME PLACE.

IMPROVEMENT IN TRANiIVIELS FOR ELLIPSES.

Specilieation forming,- part of Letters Patent No. 53.5241, dated March27, 1866.

To all whom it may concern: y

Be it known that I, CHARLES CROW, ot' Onarga, in the county of Iroquoisand State of Illinois, have invented an Improvement. in Grad uating=Tramm els 5 an d I do hereby declare that the following` is a full andexact description thereof, reference being,` had to the accompanyingdrawings, and to the letters ot' reference marked thereon, in which-Figure l is a plan view of my improvement in graduating-trammels. Fig. 2is a longitudinal elevation ofthe same. Fig. 3 is a perspectiverepresentation of one ofthe slides operating` in the grooves of thetrammel-bed.

The object ot' my invention is to make five or more holes in the sweepot' the elliptical trammel, in which holes screws or pins may beinserted into the slides operating in the grooves of the bed-plate, andin graduating these holes, by numbers, so that the relative length ofthe major and minor diameters of the ellipse to be struck may bedefinitely ascertained and understood.

To enable others skilled in the art to make and use my invention, I willdescribe the method of constructing' and using` the same.

A represents the common elliptical bedplate, containing,` the grooves C(l, in which operate the slides K, as shown at Fig. 3.

B shows the sweep, which revolves upon the top ot' the bed-plate A inthe usual manner. D represents the adjustable sweep-head, th rough caltrammel, I will reler especially lo my improvement, which consists inmaking ve or more holes, as shown at 3' l i. l 3, through each of whichthe screws E may be inserted into the holes X of thc slides K. Thescrews E may be changed from one hole to the other for the purpose ofstriking` ellipses of different relative diameters.

Operation: In order to strike an ellipse whose minor diametershall be tothe major diameter as seven to nine, the screws E in ust be inserted inthe holes l l', and to strike an ellipse whose minor diameter shall hetothe major diameter as 8 to f), the screws E must be inserted in theholes 2 l', as represented in the drawings. In order to accomplish thisthe sweep B must be turned round upon the bed-plate A in the usualmanner. The ellipse 1 (shown in the drawings) has diameters as seven tonine and the ellipse l 2 has diameters as eight to nine. Othercomparative diameters maybe made hy inserting the screws in the holes 3'3, or in holes represented by any other two numbers. 'Ihe size ot' theellipse must be reg;- ulated by movingl the sweep-head l) upon the.sweep B, in the usual manner.

Having thus described my device, what I claim as new, and desire tosecure by Letters Patent ofthe United States, is-

Ihe making` of ve or more holes in the elliptical trammel-sweep andgraduating` the saine, as above described, for the purpose ot' whichisinserted verticallyIhepencilormarkstriking; eliipses of differentrelative dialneing point H. F shows the set-screw, which ters, as setforth.

holds the pencil in place. G shows the screw which holds the sweep-headin the required place upon the sweep B, in the usual manner.

Having thus described the common ellipti- CHARLES GROW. WitnessesWINsLoW WooDs, H. C. MUNGER.

